1. Field of the Invention
The present invention relates to a mobile machine for compacting ballast of a ballast bed supporting a track consisting of two rails fastened to ties resting on the ballast bed, which comprises a machine frame extending in a longitudinal direction and supported by undercarriages on the track rails, and a ballast bed stabilizing apparatus vertically adjustably mounted on the machine frame, the apparatus comprising vibrator means imparting to the apparatus vibrations extending in a horizontal plane and perpendicularly to the longitudinal direction, flanged rollers spaced apart in a direction extending perpendicularly to the longitudinal direction and supporting the apparatus on the track rails for movement therealong, each flanged roller being mounted on a stub shaft, and a spreading mechanism mounted between the spaced-apart flanged rollers for changing the distance therebetween.
2. Description of the Prior Art
U.S. Pat. No. 4,046,079 discloses a dynamic ballast stabilization machine of this type, coupled to a ballast tamping machine. The machine comprises a ballast stabilizing apparatus vertically adjustably mounted on a machine frame between the undercarriages supporting the machine frame on the track rails. Flanged rollers support the ballast stabilizing apparatus on the track rails for mobility therealong. Transversely pivotal roller clamps cooperate with the flanged rollers to engage the track rails therebetween without play so that the stabilizing apparatus is held firmly on the track. In conjunction with a static load, vibrators impart vibrations to the apparatus in a horizontal plane and in a direction extending perpendicularly to the longitudinal direction of the machine frame. To prevent any play between the flanged rollers and the track rails whereon they run, a spreading mechanism is arranged therebetween to press the flanges of the rollers against the gage sides of the rail heads.